The disclosed embodiments relate to a medical device. Specifically, the disclosed embodiments relate to a pusher guide wire that delivers a stent contained in a catheter to a target site.
A stent is a medical instrument that supports the lumen of a blood vessel or a digestive organ so that the blood vessel or the digestive organ that has been temporarily expanded by a balloon catheter or the like does not constrict again. There are different types of stents which are roughly classified as balloon-expanding stents that are each expanded by a balloon catheter or the like and self-expanding stents that each naturally expand by itself. Recently, self-expanding stents that do not tend to deform by external forces have been in frequent use.
In a related-art method of delivering a self-expanding stent to a target site (see Japanese Patent No. 4498709, for example), while the stent that is provided around a pusher guide wire is contained in a distal-end portion of a catheter, the catheter is made to advance up to a target site. Subsequently, the pusher guide wire is pushed toward the distal end of the catheter. Thus, the stent is delivered from the distal end of the catheter to the target site. In the pusher guide wire disclosed by Japanese Patent No. 4498709, the stent is provided between a distal-end coil member functioning as a distal-end stopper and a proximal-end coil member functioning as a proximal-end stopper, and a resin protective film is provided between the stent and a core shaft so as to prevent the stent from coming into contact with the core shaft of the pusher guide wire.
In the above pusher guide wire, the protective film is fixed to the core shaft and is not suspended with respect thereto. Hence, when the core shaft is rotated, the protective film also rotates. Thus, when the core shaft is rotated, a frictional resistance is generated between the protective film and the stent, resulting in damage to the stent or failure in the transmission of rotation of the core shaft to the distal end of the pusher guide wire (i.e., poor transmissibility of rotation of the pusher guide wire) because of the frictional resistance generated between the protective film and the stent.